1. Field of the Invention
The present invention relates in general to the field of re-writable optical media, and more particularly to a method and system for time compensation of re-writable optical media write parameters.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems continually improve in the ability of both hardware components and software applications to generate and manage information. As the amount of information generated by information handling systems increases, storage of generated information presents an increased challenge. One solution for storing information in removable media is provided by re-writable optical storage media, such as CD-RW, DVD+RW and DVD-RAM disks, which manage information in much the same manner as magnetic floppy disks. Re-writable optical storage media use phase change technology to “burn” information into a disk by altering the reflectivity of the disk material. A recording layer is included in the disk and made of phase change material that exhibits two solid phases at room temperature with different optical reflective properties. Information is stored by switching between the two phases with a focused laser beam that is pulsed in specific sequences in which the intensity and duration are varied to selectively alter the phase change material into the two phases. The information is read from the disk by illuminating the phase change material at low power with the focused laser and measuring the reflectivity of the phase change material. Most rewritable optical storage media withstand approximately 1000 rewrites before the written bit boundaries acquire too much noise for reliable read back. Some media, such as DVD-RAM withstand over 100,000 rewrites. In the following, the 1000 rewrite example will be used for demonstrative purposes.
One problem with re-writable optical storage media is that different media types and phase change materials can have varied phase change properties over time. In particular, phase change recording layers for higher speed recording are difficult to design since the melting, cooling and annealing properties of the materials have to be balanced. For example, with currently available phase change materials, recording speeds over 4 Mbytes/s, equal to 32×CD-RW or 4×DVD+RW, result in less consistent rewrite properties and different write requirements when recording for the first time versus subsequent recording. Under such conditions, if an optical storage medium is consistently recorded with the same initial power conditions, information stored on the optical storage medium becomes less reliable with a lower signal-to-noise ratio and the practical number of rewrites becomes substantially reduced, such as reduced from 1000 specified re-writes to less than 100 actually supported re-writes. Moreover, optimal recording subsequent to an initial recording often exhibits different responses with different time periods between the initial recording and the subsequent recording.